The embodiments disclosed herein relate to a method and system for printing personalized medication such as tablets.
By way of background, a tablet is a pharmaceutical dosage form. It typically comprises a mixture of active substances and excipients, usually in powder form, pressed or compacted from a powder into a solid dose. The excipients can include diluents, binders or granulating agents, glidants (flow aids) and lubricants to ensure efficient tableting; disintegrants to promote tablet break-up in the digestive tract; sweeteners or flavors to enhance taste; and pigments to make the tablets visually attractive. A polymer coating is often applied to make the tablet smoother and easier to swallow, to control the release rate of the active ingredient, to make it more resistant to the environment (extending its shelf life), or to enhance the tablet's appearance.
The compressed tablet is the most popular dosage form in use today. About two-thirds of all prescriptions are dispensed as solid dosage forms, and half of these are compressed tablets.
One of the biggest issues facing pharmacists is ensuring that patients understand what the medication is used for and how to take their medications correctly, i.e., the right drug, the right time, etc. It can be especially confusing for elderly and mentally challenged patients who are on, for example, as many as ten different drugs a day. Also, today's tablets are produced in discrete quantities of active pharmaceutical ingredients (API). A ninety pound person and a three hundred pound person may be prescribed the same quantity of medication. For composite medications such as a vitamin, everyone presumably takes the same dose regardless of the need.
Tablets are produced pretty much the same way whether in pounds or in tons, depending on their medical purposes and newness. There is also a demand for better methodologies in achieving more rapid prototyping and time-to-market.
The tablet fabrication process has not changed much in principle, except for advancements in technology and quality controls. Tablets are typically large, not for medical purposes, but for ease of handling. Tablets have many shapes and colors so that they can be distinguished. Tablets may be stamped with symbols, letters and/or numbers for ease of identification. Tablets may be designed for ease of swallowing with control agents added for releasing API through dissolution or disintegration in the digestive tract. Tablets generally start as dry powder or granules. The powders typically have particle sizes of 3-30 ums. Granule sizes are generally between 45-450 ums. Additives to tablet binders include, for example, API, excipients (pharmaceutically inactive ingredient), disintegrants, lubricants, and additives for flow. Typically 99.9% of the materials in a tablet are NOT API.
The manufacturing process of powders or granules for forming tablets is actually quite similar to toner manufacturing. There are two basic granulation techniques. Wet granulation is where a liquid binder is used to agglomerate the powder mixture. After the granules are dried, they are screened for size uniformity. In dry granulation, a powder is compacted by application of a square low pressure force and then it is broken up gently to produce granules. After granulation, the material is then blended with powder lubricants. In addition to granulation, hot melt extrusion is a modern technology used to produce powders for drugs. Output from the hot melt extrusion can be pellets or spheroids. The polymers used for the hot melt extrusion have glass transition temperatures between 90 to 150° C. The overall property of medicament powder is similar to xerographic toners (minus charge control agents).
Tablet diameter and shape are determined by the die used to produce them. The die generally has an upper and a lower punch. The tablet thickness is determined by the amount of material and the position of the punches in relation to each other during compression. The input materials to fill the die are granules. The compression of tablets is similar to pressure fusing of toner particles without external thermal heat source in principle.
Because of the “pressure fusing” manufacturing process, the resulting tablets generally have a range of porosity of between 5 and 20%. Tablets need to be hard enough so that they do not break in the bottle and resist the stresses of packaging, shipping and handling by pharmacists and patients; and yet still be friable enough to disintegrate in the gastric tract. Tablets may be coated to further ensure this requirement. Coatings also prevent tablets from sticking to each other, help to reduce unpleasant tastes, provide a smoother finish for ease of swallowing, extend the shelf life of components that are sensitive to moisture or oxidation, and protect light-sensitive components from photo degradation. The coatings are typically polymer and polysaccharide-based, with plasticizers and pigments.
There are at least two issues for patients: (1) managing and taking the pills and (2) taking the right amount. Many seriously ill and long-term patients take many pills a day, and it can be a struggle for some of them to consume some 10-15 pills at a time. For some elderly and mentally-challenged patients, in addition to taking many medications each day, it can be difficult for them to manage their pills. In the best case, all patients should take the quantity of medication that is the most suitable for them. Techniques that pharmacists currently use to help patients manage their medications include, for example, weekly pill boxes (someone lays out all the tablets by time of day), alarms (replace the cap from the pharmacy with a special computerized one that rings when the patient needs to take a dose of a medication), and text messaging.
In the United States, pharmacists generally repackage medications from a stock bottle (usually containing quantities of 100 tablets) into a smaller bottle that is labeled for a specific patient. In Europe, the pharmacists tend to use blister packs (also referred to as “unit dose” packaging).
Today, tablets are produced from pounds to tons in weight, depending on the need and the newness of the medication. There is also a need for rapid prototyping, shorter trial duration, faster FDA approval, and especially a desire to quickly bring new medications to seriously ill patients.